Excision repair cross-complementing 1 expression protects against ischemic injury following middle cerebral artery occlusion in the rat brain

To study the effects of excision repair cross-complementing 1 (ERCC1) on the pathophysiological process of brain ischemia, we examined the changes in ERCC1 expression, as well as the functional significance of ERCC1 in the rat brain following middle cerebral artery occlusion (MCAO). The results were as follows: (1) ERCC1 immunopositive cells were widely distributed in various brain regions. ERCC1 expression was localized to the nuclei of neurons and astrocytes. (2) ERCC1 expression, as determined by western blot, increased at 3 days, remaining until 14 days, in the ipsilateral cortex and striatum following MCAO. Immunohistochemical analysis demonstrated that ischemia induced increased ERCC1 expression within the periinfarct core, with increasingly less expression toward the core. (3) Knockdown of ERCC1 expression by intraventricular injection of antisense plasmids increased DNA damage and infarct volume in the ischemic brain. (4) ERCC1 overproduction, by injection of expression plasmids, significantly reduced infarct volume and the accumulation of DNA-damaged neurons. Taken together, these results indicate that both endogenous ERCC1 and exogenous ERCC1 have an important neuroprotective function in the brain. In addition, administration of ERCC1 to the brain could prove to be a successful strategy for neuronal protection against ischemic injury.